Fuck that, I aint hitting anyone with MY bass, I payed too damn much for the ones I own.

Now the drummers sticks are nice and pointy shaped, and go great into a persons eye. Or grab the guitarist's guitar, they half expect the guitar to be broken over someone or something before their music career ends.

Best bet though, is to be honest with the dude. Let him know what is going on, and see what his thoughts are.

I mean, I love the whole "Its better to ask for forgiveness then permission" thing usually, but I see that possibly leading to problems down the road one way or another, and its always better to be safe then sorry.